An influential article in the journal Progress in Neurobiology provided one of the first comprehensive reviews of how estrogen potentially can protect against Alzheimer’s disease and other neurological disorders.

But there also are risks. The Women’s Health Initiative found that taking estrogen plus progestin increased women’s risks of heart disease, blood clots, stroke and breast cancer.

DonCarlos and other researchers are studying agents called selective estrogen receptor modulators (SERMs) that potentially could provide the benefits of estrogen without the risks. One such agent is tamoxifen, which reduces the risk of breast cancer by blocking estrogen receptors in the breast. In the bones, tamoxifen has the opposite effect by acting like estrogen. This has the beneficial effect of reducing the risk of osteoporosis, DonCarlos said.

"We are looking for other SERMs that potentially could help protect the brain, without increasing the risk of breast cancer or other negative effects," DonCarlos said.

Most studies suggest that estrogen has beneficial effects on cognitive function, DonCarlos added. "But we still have a lot of research to do before recommending the use of estrogens in the clinic for this purpose."